Electromagnetically controlled switching devices



y 1960 J. M. N. HANLET 2,936,353

ELECTROMAGNETICALLY CONTROLLED swxwcmuc DEVICES Filed Dec. 17, 1956 ELECTROMAGNETICALLY CONTROLLED SWITCHING DEVICES Jacques Marie Noel H anlet, Paris, France, assignor to gociete dElectronique et dAutomatisme, Courbcvoie,

rance Application December 17, 1956, Serial No. 628,642

Claims priority, application France December 23, 1955 15 Claims. (Cl. 200-94) The present invention relates to electromagnetically controlled switching devices for galvanically or otherwise coupling and decoupling electrical circuits.

An object of the invention is to provide electromagnetically controlled switching devices for such a purpose which present a very short time of changeover from one of their steady conditions to the other one of these conditions, and conversely, without any bouncing effect of the mechanically displaced part thereof during and after such changeover action occurs therein when their electromagnetic drive produces the actuation thereof. very short time implies that a changeover is, formstance, elfected with a delay shorter than a millisecond from the instant at which the said drive is operated through a sudden variation of the control current therefor.

It is a further object of the invention to provide such switching devices which couple and decouple galvanic connections that currents of a relatively high value, for instance of several amperes, can pass through the switch contacts whilst only very small values of the driving current, for instance of the order of 20 to 25 milliamperes, are applied to the electromagnetic control thereof.

The action of a stationary magnetic field upon a movable electric circuit is well known per so: when an electrical current is applied to the said circuit, this circuit is suddenly thrown in a direction perpendicular to the lines of force of the said magnetic field and defined in accord ance with the well-known law of Laplace.

I An electromagnetically controlled switching device according to the invention is mainly characterized in that it comprises in combination at least one fiat spiralled winding and a flat supporting element therefor, a stationary magnetic circuit comprising a correspondingly flat airgap wherein the said winding is supported from the said element, an axle external to the said air-gap and around .which the said supporting element can be angularly dis- Such a placed and electrical circuit switching means controlled K from the said angular displacement in accordance with the relative positions of the said winding and the said airgap according to the condition of current through the said winding.

This and other features of the invention will be. described in detail with reference to the accompanying drawings, wherein:

Fig. l is a partial cross-section of an illustrative embodiment of the invention;

Fig. 2 and Fig. 3 respectively show the two sides of the movable member thereof;

Figs. 4 and 5 respectively show the two conditions of the device illustrated in Figs. 1, 2 and 3, when combined with abutment means and electric switching means, for completion thereof; and Fig. 6 shows an illustrative embodiment of a set of .contacts controlled from the arrangement disclosed in the preceding figures.

Referring first to Figs. 1 to 5, a dielectric slab 1 is provided as a supporting member for an electrical winding 2,936,353 Patented May 10, 1960 ment of the magnetic circuit pole-pieces to be hereinbelow ascertained.

The ends 8 and 9 of the said winding are connected through flexible conductors 10 and 11 to respective terminals 12 and 13. These terminals may be supported by a portion 14 of the casing of the device and said casing is not otherwise shown in the drawings. At the ends 8 and 9, metallic rivets or eyelets may for instance be in-' serted in the dielectric slab and the conductors 1G and 11 soldered therein. The lengths of the said conductors are such that no mechanical stress is applied thereto in the one and the other of the two positions of the slab, Figs. 4 and 5. Fig. 4 is for instance the rest position of the device and Fig. 5 shows the work position thereof.

Now the winding 2-3--4-5 may advantageously be obtained from one of the so-called printed circuit techniques. For instance the dielectric'slab 1 is first completely coated on both its faces with a metallic film, preferably by means of an evaporation under vacuo process. Two holes 6 and 7 have been previously made in the dielectric slab so that these holes are also coated with the said metallic filrn- Then a photographic film is coated upon both the said faces and receives the pic tures of the coils and interconnections therebetween and connections thereto. After development of these pictures, washing and drying thereof, the member is put within an acid bath which dissolves all the parts of the metallis a-' tion not protected by the photographically deposited resist or film. In devices according to the invention, it may be further useful to reinforce the lines of the coils through an electrolytic deposit process but most often this step will be unnecessary with respect of the values of current which are due to pass through the winding. On the other hand, as well known per so, such a printing technique enables the production of very thin conducting lines and spacings therebetween.

The slab 1 is mounted for at least an angular displacement around an axle 17 for instance connected through torque spring connections 18 to the walls 19 and 20 of the casing of the device. These springs may be such that in the rest condition of the device, no current being impressed upon the winding thereof, the movable member is forced to the position shown in Fig. 4, a tail part 15 of the slab 1 resting against an abutment piece 25 afiixed to the wall 14.

A pair of magnetic pole-pieces of opposite polarities cooperates with each part of the winding. The polepieces 21(N) and 22(5) define an air-gap within which the pair of coils 2-3 is located. The pair of pole-pieces 23(N) and 24(5) define another airgap within which is located the pair of coils 4-5 of the winding. These pole-pieces may be made from separate small magnets, which are commercially available or, of course, may be the pole-pieces of a complete magnetic conventional circuit. In either case, the magnetic circuit is affixed to the casing of the device in such a way that, as clearly shown in Fig. 4, the pole-pieces are set to face the portions of the Winding which are of an upward direction of circulation of current therethrough. This illustrative condition may be modified at will. The direction of the driving current is indicated by arrows in Figs. 2, 3 and 5. Consequently, when this current is applied to the device, the coils 2 and 3 will be acted upon, so that the upper part of the movable member Will be suddenly pushed forward in the left-hand direction (with respect to the drawing) whereas the pair of coils 4 and 5 will he suddenly pushed forward in the right-hand direction. The movable member will change its position and such denly comes to the position shown in Fig. 5, the tail end 15 of the slab 1 abutting against an abutment member 26 affixed to the Wall 29 of the casing of the device. This angular displacement occurs against the action of the springs 18 supporting the axle 17.

When the driving current is interrupted at the terminal 12-13, the reset torque from the springs 18 will suddenly reset back the movable member to its rest posi tion.

. The part of the device just herein above described constitutes the control arrangement thereof. The movable slab 1 with the windings mounted thereon constitute the armature of the device. An electric circuit switching element, at least, must be associated therewith and such an element is shown as 27, Figs. 4 and 5. This element 27 may be mounted upon a socket 28 wherein terminals such as 30 are provided for the electrical interconnec tion of the device with utilisation circuits and com ponents, not shown as not being part of the invention.

If, for instance, the member 27 consists of two separate metallic slabs between which the insulating portion 16 of the movable member comes when the device is activated, a change of capacity is obtained; the part 16 may be metallic or metallized if a movable condenser armature is necesary for such a change of coupling.

If, alternatively, the member 27 comprises a pair of spaced coils serially interconnected or otherwise, the part 16 may then be of magnetic material in order to vary the self-inductance or mutual inductance between these coils. Further, if required, the part 16 may bear a further winding supplied with some utilisation current.

Alternatively again, the member 27 may be made in a piling or electrical make-and-break contacts, the part 16 of the movable member thus ensuring their operation according to the control current through the winding 2 to 5 of the device.

Of course, when required, a similar member 27 may be associated with the rest position of the control arrangement.

The part 16 actuated by the said control arrangement may be, if wanted, a member separate from the tail 15 of the movable slab. For instance, this part may com prise a cam arrangement cooperating with the axle 17, for instance through the actuation of one or more levers from the rotation of the said axle. H Considering for illustrative purposes a relay arrange ment according to the invention, the contact part there of may be such as disclosed in the scheme of Fig. 6. Such a relay will for instance operate in electrical circuits passing several amperes and present a contact pressure as high as 20,000 dynes, though changing over its condition within one millisecond of time.

In this contact arrangement, there are two elastic blades 27 which bear electrical contacts 38. Rigid armatures 31 are placed on each side of the said blades 27 and bear electrical contacts 32. The output terminals 30 are supposed connected to the said contacts 32 through the armatures 31. Each blade 27 is terminated by a small cage 33 housing a ball 34. Suitable holes in these cages enable the balls to protrude within the spacing between the blades 27. In the rest condition, which is shown, the pairs of contacts 32-38 are opened. When the part 16 of the control arrangement is forced between the balls, the contacts close and consequently the device acts as a two work contact relay. However, the speed of travel of the part 16 is not substantially reduced when said part engages the balls due to the quite small friction therebetween. Of course, a greater number of relay contacts may be introduced through apparent piling of elastic blades inter-associated through bars or pushers, with fixed armatures therebetween.

A damping of the movable element may be obtained by electrical means such as the insertion of a damping resistor in series with the energization winding thereof. Such a provision will balance out the stray E.M.F. which may be induced within the energization winding coils from the magnetic field when these coils are in movement with respect to this field.

Whereas a first manner of embodying the movable member has been previously described with reference to the conventional printed circuit technique, it is thought preferable to obtain a more suitable supporting element as follows: the dielectric slab is replaced by a slab of pure aluminium coated with alumina for instance through submitting it to an anodizing process. As wellknown, the alumina is a very good insulator. Such a slab is then printed as described. The internal metallic plate of aluminium will operate as a short-circuited secondary winding and will oppose the induction in the external winding 2 to 5 of a current of reverse direction with respect to the direction of the energization current therethrough when the member moves in the fixed magnetic field of the pole-pieces.

In another respect, the movable member may be made with out any printing at all and for instance as follows: a metal laminate is first coated with an insulating oxide, as abovesaid, and then wound into a roll. Spiralled elements are then cut therein, and consequently induct ance elements having a great many number of turns are obtained, the thickness of which is of the same order as it has been the case with the printed technique. The dielectric part in such spiralled coils as cut from such a roll of laminated metal is quite negligible. The cutting operation does not produce any short-circuit between the turns if, on each element which is cut oif the roll, there is made a brushing operation with diluted acid for removing any protusions of the metal therein, and if, after it has been washed and dried, a protective resist of varnish is deposited upon the element. This protective coating may be such as to facilitate the fixation of the coil element within a frame, by glueing and/ or heating, for obtaining the final product which must be used as a movable part in the switching devices according to the hereinbefore disclosed provisions.

The electrical connections of the movable part have been described as flexible conductors connected to fixed terminals mounted upon the casing of the device. Said connections may also and in an alternative Way comprise a connection through the axle 17, which is made conducting, and a connection through an insulated wire applied along the said axle.

In a further detail alternative, each of the coils of the windings may be terminated at points which are symmetrical with respect to the axle 17 and wires, parallel to the axis of17 but spaced therefrom, may be used for the supply of the control winding. When the movable member is suitably light, the axle 17 may then be omitted.

I claim:

1. An electromagnetically operated control device comprising a pair of spaced magnetic pole pieces of opposite polarity and defining between them an air-gap providing a flux path, a movable support member fixedly carrying at least one fiat spiral coil in a plane passing through said air-gap transversely of the flux path, means mounting said support member for movement of said coil in its own plane and transversely of said magnetic flux path between two fixed stops, one defining a rest position and the other a work position for the support member, a circuit for electrically energizing said coil to produce a magnetic field which interacts with that of the magnetic flux to cause movement of said coil in said gap and corresponding movement of said support member, and biasing means for positioning said support member against the rest stop atone end of its movement with the coil partly in said air-gap when no current is flowing therein;

2. A device in accordance with claim 1 in which the, support member is mounted to turn about an axis spaced from said air-gap. V

3. An electromagnetically operated control device com; prising a pair of spaced magnetic pole pieces of opposite polarity and defining between them an air-gap providing a flux path, amovable support member carrying at least one fiat spiral coil, means mounting said support member for movement of said coil in its own plane and into said gap transversely of said magnetic flux, said support member being movable between a rest portion and a work position, means normally biasing said support member to therest position, a circuit for electrically energizing said coil to produce a magnetic field which interacts with that of the magneticiiux, to cause movement of said coil in said gap and correspondingmovement of said support member, said member carrying thereon a second flat spiral coil spaced from said first-mentioned coil, 2. second pair of pole pieces of opposite polarity and defining between them a second magnetic air-gap in which the fiux is substantially transverse to the plane of the second coil and in the path of movement thereof, the spacing between the gaps in the direction of movement of the coils being such that as the first coil moves out of the first air-gap the second coil moves into the second air-gap, said second coil being connected to said energizing circuit to produce a magnetic field in such relation to the fiux in the second air-gap that. the second coil tends to move said support member in the same sense as the first coil.

4. A device in accordance with claim 3 in which said flux paths have parallel axes, the movable support member being pivoted about an axis parallel to and spaced from the magnetic flux path, the coils being mounted on opposite sides of said axis.

5. An electromagnetically operated control device comprising two spaced pairs of magnetic pole pieces, each pair defining an air-gap providing a flux path, said paths being in parallel, a support member movable transversely of said flux paths between a rest position and a work position, means normallybiasing said support member to the rest position, flat spiral coil means fixedly carried by said member in a plane transverse to the flux paths and having a greater portion thereof in one flux path than in the other and a circuit for electrically energizing said coil means to provide a magnetomotive force acting to move the coil means to position a lesser portion thereof in the one path and a greater portion thereof in the other path and to produce cor-responding movement of said support member.

6. An electromagnetically operated control device comprising a support member mounted to move in a plane between two fixed stops, means normally biasing said support member in rest position against one of said stops, a pair of spaced, fiat spiral coils fixedly carried by said member parallel with said plane and in axial alignment with each other, magnetic pole faces defining at least one flux path transverse to said plane through which the coils move, said coils when at rest having a predetermined number of turns in said flux path, and a circuit for energizing said coils in such a direction as to produce a magnetomotive force to move said member from one position to another to position a difierent number of turns in said fiux path.

7. A device according to claim 6 wherein said support member comprises a flat plate of non-magnetic material having said coils mounted on opposite faces thereof.

8. A device according to claim 7 wherein said fiat plate is a metal plate insulated from said coils.

9. An electromagnetically operated control device comprising a pair of spaced magnetic pole pieces of opposite polarity and defining between them an air-gap provid ng a flux path, a movable support member fixedly carrying at least one flat spiral coil in a plane transverse to the flux path, means mounting said support member for movement of said coil in its own plane and transversely of said magnetic flux path between a fixed rest position and a fixed work position, a circuit for electrically energizing said coil to produce a magnetic field which interacts with that of the magnetic flux, to cause movement of said coil in said gap and corresponding movement of said support member, said member carrying thereon a second fiat spiral coil spaced from said first-mentioned coil, a second pair of pole pieces of opposite polarity and defining between them a second magnetic air-gap in which the flux is substantially transverse to the plane of the second coil and in the path of movement thereof, the spacing between the gaps being such that the first coil has a greater portion thereof partially within the first flux path than the second coil has within the second flux path when the coils are deenergized and said support member is in rest position, said coils being connected in said energizing circuit to produce magnetic fields in such relation to the flux in their respective air-gaps as to move the coils to decrease the portion of the first coil and in crease the portion of the second coil within their respective flux paths and to produce a corresponding movement of the support member.

10. An electromagnetically operated switch device comprising a pair of spaced magnetic pole pieces of opposite polarity and defining between them an air-gap providing 'a flux path, a movable contact-operating armature member fixedly carrying at least one flat spiral coil in a plane transverse to the flux path and partially within the path when at rest, means mounting said armature member for movement of said coil in its own plane and transversely of said magnetic flux path between a fixed rest position and a fixed work position, a circuit for electrically energizing said coil to produce a magnetic field which interacts with that of the magnetic flux, to cause movement of said coil in said gap and corresponding movement of said armature member, said armature member comprising a flat plate of non-magnetic material having said spiral coil secured to one face thereof.

11. A device according to claim 10, wherein said spiral coil is formed of a thin metallic strip having the individual turns thereof bonded to one face of said flat plate.

12. An electromagnetically operated switch device comprising a pair of spaced magnetic pole pieces of opposite polarity and defining between them an air-gap providing a fiux path, a movable contact-operating armature member fixedly carrying at least one flat spiral coil in a plane transverse to the flux path and partially within the path when at rest between a fixed rest position and a fixed work position, means mounting said armature member for movement of said coil in its own plane and transversely of said magnetic flux path, a circuit for electrically energizing said coil to produce a magnetic field which interacts with that of the magnetic flux, to cause movement of said coil in said gap and corresponding movement of said armature member, said armature member comprising a thin metallic plate coated with a thin film of the oxide of the metal of said plate, and said spiral coil being bonded to one face of said plate.

13. An electromagnetically operated control device comprising a pair of spaced magnetic pole pieces of opposite polarity and defining between them an air-gap providing a flux path, a movable support member fixedly carrying at least one flat spiral coil in a plane transverse to the flux path and partially within the path when at rest, means mounting said support member for movement of said coil in its own plane and transversely of said magnetic flux path, a circuit for electrically energizing said coil to produce a magnetic field which interacts with that of the magnetic flux, to cause movement of said coil in said gap and corresponding movement of said support member, said coil being formed of a tight roll of a thin stfip'of metalha'ving" an insulating" la'ye'r'on at least one face thereof.

- 14.- An electromagnetically operated control device comprising a pair of spaced magnetic pole pieces of op-' face thereof,- the individual turns of said coil being' bonde'd to one face of said plate.

-15.- A device according to claim 14 wherein the said in sulating layer consists of an oxide film of the metal conposite polarity and defining between them an air-gap pro- 5 stit'ut in Said chilviding a flux path, a movable support member fixedly carrying at least one flat spiral coil in a plane transverse to. the flux path and partially within the path when at rest, means mounting said support member for movement of said coil in its own plane and transversely of said 10 magnetic flux path, a circuit for electrically energizing said coil to produce a magnetic field which interacts with that of the magnetic flux, to cause movement of said coil in said gap and corresponding movement of said support member, said support member comprising a flat plate and said spiral coil comprising a tight roll of a thin strip of metal having an insulating layer on at least one References Cited in the file of this patent UNITED STATES PATENTS 502,449 Verley Aug. 1, 1893 602,527 Sullivan Apr. 19, 1898 2,135,171 Chireix Nov. 1, 1938 2,252,438 Petersen et a1 Aug. 12, 1941 2,573,000 Fischer Oct. 30, 1951 2,573,183 Chudyk Oct. 30, 1951 15 2,799,746 Raymond July 16, 1957 FOREIGN PATENTS 362,116 Great Britain Dec. 3, 1931 

